HIIT: Benefits, Precautions and Clinical Considerations
Parbhat | Updated: Nov 29,2022, 02:45 AM IST

HIIT: Benefits, Precautions and Clinical Considerations

What is HIIT?

The abbreviation HIIT stands for “High-Intensity Interval Training”. HIIT is a method that allows the improvement of muscle strength and endurance. In a HIIT routine, high-intensity exercises are alternated with low-intensity exercises. The following describes the contraindications and benefits of HIIT to say yes or no to this training method.

In a HIIT training routine, it is usually alternated between about 20 seconds of high-intensity exercises, with 20 seconds of cardio exercises and the following 10 are rested. The idea is to combine exercises that increase the heart rate (for example, running at maximum speed) with strength exercises and rest. The cycle is repeated about 4 times.

HIIT benefits

HIIT workouts are ideal for those who are carrying out weight loss processes. Its benefits are to reduce the body mass index, accelerate the metabolic rate and reduce the percentage of body fat. It is a method proposed by coaches for overweight people.

The benefits of HIIT are:
• Increase respiratory capacity
• Accelerate the basal metabolic rate
• Increase testosterone levels
• Remove body fat
• Short duration and easy adaptation

1. Increase respiratory capacity
Studies confirm an increase in aerobic endurance, maximal oxygen consumption ( VO2 max ) and peak oxygen consumption (VO2 peak) when doing HIIT. Some authors affirm that with only 2 months of adaptation, significant changes are generated in the ability to transport and absorb the amount of oxygen in the blood.

2. Accelerate the basal metabolic rate (BMR)
This is one of the controversial benefits of HIIT. Some authors claim that HIIT accelerates the basal metabolic rate. However, there are still studies to be done to confirm it. What has been proven is that one of the benefits of HIIT is to normalize glucose metabolism, ideal for preventing chronic diseases such as type 2 diabetes.

3. Increase testosterone levels
By performing high-intensity interval workouts, testosterone can be increased. This is explained by intensity. By working to the fullest, the body releases a greater amount of sex hormones to counteract the effects of muscle stress.

4. Remove body fat
The main benefit of HIIT is the ease in which a person can eliminate body fat. This training method was specially designed for those who have problems of overweight and obesity.

5. Short duration and easy adaptation
The last benefit of HIIT is its short duration. If you are one of those who always run to get to the office and go to the gym Or try to study and exercise at the same time, the high-intensity interval system is ideal for you. You are good to go with just 30 of training, not to mention that it is one of the methods with the best adaptation potential and does not require a lot of equipment.

Does HIIT work?

When working at the low intensity the slow muscle fibers are the ones that work; This type of fiber uses fat deposits as a source of energy. When working with high-intensity loads, what is worked on is fast muscle fibers, the type of fiber that uses muscle glycogen as energy.

In a HIIT workout, both intensities alternate allowing the development of the two types of muscle fibers. This fact and the improvement of the cardiovascular system are the main benefits of HIIT.

This training system has been used with excellent results to reduce obesity in children and people with high levels of a sedentary lifestyle.

Metabolism and HIIT

In HIIT workouts, the difference between intensities and loads allows the body to better use fatty acids as a source of energy. It is for this reason that some authors maintain that HIIT can accelerate metabolism.

The use of slow muscle fibers does not occur in a traditional gym routine, which leads to the need to complement it with aerobic exercises. HIIT workouts focus on the number of repetitions and allow myofibrillar muscle hypertrophy to work.

HIIT Clinical Precautions

High-intensity interval training is not for everyone. If you have not trained for a long time, it is not good to start with a return to physical exercise with HIIT. HIIT contraindications are detailed below:

1. People with problems or injuries to joints and tendons
If you have experienced a knee or shoulder injury, you should look for other high-intensity exercise options that do not involve joint impact. Loads at high intensities can be dangerous in rebuilding injuries to joints and tendons. On the other hand, the use of supplements such as hydrolyzed collagen, glucosamine and chondroitin sulfate have been proven effective in preventing joint wear.

2. People with respiratory problems or asthma
You have to have a good aerobic base to start training at high-intensity intervals. People with asthma or respiratory problems should not start HIIT without first trying other light and medium intensity workout methods.

3. People who take blood pressure medications
One of the contraindications of HIIT is that this type of training is not recommended for people who take blood pressure medications. Working at high intensity can cause severe cardiac events.

4. Pregnant women
Pregnant women should not do HIIT. Sudden movements, jumps, and fast heartbeat can cause problems in the fetus. Although this training method is effective to reduce the extra kilos after pregnancy, during the pregnancy, other types of lower intensity exercise routines such as Pilates are recommended.

5. People with uncontrolled diabetes
One of the contraindications of HIIT is for those with uncontrolled diabetes. Special care should be taken in doing activities of this type. Calorie expenditure is usually high and hypoglycemia events can occur.

6. Injuries to the knee or shoulders
If you have experienced a knee or shoulder injury, you should look for other high-intensity exercise options that do not involve joint impact. Loads at high intensities can be dangerous in rebuilding joint and tendon disorders.

Tips on starting HIIT

When training at high-intensity intervals, precautions must be taken to be able to finish the sessions without problems. Here are 5 tips to follow when starting HIIT:

1. Do not combine with thermogenics
The thermogenic like caffeine are not recommended with a HIIT workout. These substances increase blood pressure and heart rate, which can cause damage to health as HIIT too accelerate heart rate and blood pressure.

2. Drink homemade isotonic drinks
When doing HIIT, the loss of water due to sweating is usually excessive. The sports drinks can help a person does not become dehydrated after a training session.

3. Do not go to the sauna after training
Going to the sauna after training can cause low blood pressure and even fainting. High temperatures can have negative repercussions on the cardiovascular system. If you opt for a muscle recovery method we recommend contrast douche or myofascial release.

4. Do not combine it with the ketogenic diet
If you are doing the ketogenic diet or other low carb diet do not combine it with high-intensity interval training. Performing this type of training with very low glucose levels can lead to loss of consciousness.

5. Drink more water in the day
When doing HIIT you are likely to sweat in bulk. It is important to know that the amount of water that should be taken in the day increases by at least 500 mL when doing HIIT. If the cost of water through sweat is not compensated, mild symptoms such as dry and severe skin may appear; as kidney disorders.


  • High-intensity Interval Training or HIIT consists of replacing maximum-intensity exercises with low intensity or aerobic exercises.
  • The rest between sets is minimal.
  • This training method is one of the best workouts to eliminate body fat.
  • A lot of calories are burned doing HIIT. However, the theory that it is capable of accelerating metabolism has not yet been proven by experts.
  • Training at high-intensity intervals is dangerous for beginners or people who are not accustomed to exercising regularly.
  • HIIT routines resemble other methods such as circular training, calisthenics, and Tabata.